(Mk1) IR Remote Repair & Re-Sync

From French Car Wiki
Jump to: navigation, search

Go to Xantia Wiki Homepage


The Infra-Red (IR) Remote 'plipper' for our Xantia ('95 S1) went intermittent, then stopped working. The red indicator LED was lighting but perhaps rather feebly. Taking it apart to change the batteries, I noticed the Infra-Red L.E.D. had a broken leg where it was bent through a sharp 90º. A very awkward spot to reach, but I managed to put a spot of solder in the angle – bingo! remote working again and at longer range than before. But this only lasted a few weeks; this time, not only had the repair had broken (as I feared it might), but the other leg had also fractured in the same place.

The various charges for an order of a single packet of IR LEDs from an electronic wholesaler would have made the one LED I needed very expensive. But for £1 from a local charity shop, I bought a working TV remote control, which from the outside looked as though its LED might have legs of usable length. You can check any IR remote control by looking at the business end via an old/cheap digital camera (mobile, web cam) - I've found that 'better' cameras (like my Nikon compact) filter out IR. If it's working, the IR LED will flash white on the screen (Photo 5). First test the camera with any known working remote (TV, DVD, Sky box) and then the donor remote with the 'proven' camera.

Photo 1

What I found when I opened the Sony remote's case (Photo 1) was better than I hoped. I could have cut the LED off the PCB, but to give me the maximum length to work with, I un-soldered the legs from the other side of the PCB.

Sequence of operations

  1. Remove the plipper batteries and unsolder the remains of the old LED - be very careful not to damage the PCB with too much heat.
    Photo 2
  2. Remove the 'new' LED from the scrap remote; Photo 2 shows roughly how much leg length you need.
  3. Carefully straighten the LED's 'legs'.
  4. Before re-bending the legs, it's essential to get the LED in the correct orientation/polarity.
    Photo 3
    In Photo 3 the orientation of flat (in red) on the body of the LED. Ignore the arrangement of the LED's visible internals - they may be either way round.
  5. Bend the legs by holding both legs by the 'stops' (fat bits visible in the first photo) in a pair of small pliers so that the edge of the jaws lines up with the end of the stops nearest the LED body. Gently push the body through a right-angle. This should give you a gentle radius (no sharp corner) as in Photo 2.
    Photo 4
  6. Fit the LED so that it is vertically central (in the orientation of the photos) on and touching the black plastic support. Tack-solder both legs and cut off any excessive leg length (not too short or you may not have enough to play with).
  7. Test fit the PCB into the case and adjust the position of the LED if necessary. Trim the legs to the same height as the other components and solder the joints properly. Don't overwork the solder joints or the copper 'tracks' will come unglued from the PCB and then you are in trouble!
Photo 5
  1. Refit the batteries (Photo 4) – note correct orientation.
  2. Re-assemble the plipper and test (Photo 5) using the 'proven' camera.


All remotes need to be synchronised with the central-locking/alarm of the specific car. While it's usual to talk about "programming the remote", it's really a matter of 'registering' the remote's code in the central-locking ECU's memory.

The central-locking ECU goes into programming mode when it detects that both buttons of any remote have been pressed immediately after the ignition is turned ON. The ECU will then stay in programming mode until the ignition has been off for 2 minutes.

How to Sync a Single Remote

Without a spare key you need to take the electronics out of the remote's case so that you can aim the LED at the sensor 'dome' in the roof above the rear-view mirror while the key is in the ignition.

Turn the ignition on to the second (all instrument panel warning lights) ON position, and, with the remote pointing directly at the receiver, immediately press the remote's Lock button (1) then the Alarm (2) button, repeat buttons alternately several times.

Remove key, wait a good couple of minutes before trying the plipper. Beware, the “CRASH” as the doors all lock is a lot louder inside the car than out!

Synchronising Two Remotes

The central-locking controller has several (4?) memories for remote codes, and each time it detects a valid remote code while in programming mode, it will fill another memory. Pressing the remote buttons several times allows for codes which might not be correctly received, and ensures that all the memories are filled with something useful.

As it's vital to start synchronising by pressing the remote's buttons as soon as the ignition is turned on, an 'assistant' to turn the key on command is essential.

The best strategy would seem to be to fill all 4 code memories with the code for the first remote as above for a single remote, four times over. Then immediately sync the second remote twice ONLY. This should now mean that two memories hold the code for Remote 1 and two hold the code for Remote 2.

Switch off, remove key from ignition and wait the essential couple of minutes before testing both remotes.

Sync Fails

Apart from the obvious reasons that either the remote doesn't send a decent signal (PCB fault or tired batteries), I suspect that the reason why many people fail in their attempts to re-sync a remote is that they don't wait the essential 2+ minutes for the ECU to re-set itself, because the Handbook doesn't mention the importance of waiting at least 2 minutes. I know I wasted a lot of time and effort doing the first step correctly several times with different, apparently working, spare PCB units before discovering the necessity of waiting patiently. I only discovered this when I had given up after several, apparently failed, attempts; I re-assembled the original remote (with new batteries) then sat in the car for several minutes quietly re-reading the handbook on the subject, thought "Bloody Citroens! Why won't ANY of these work?", pressed the Lock button once more in fury, "CRASH" - as all 5 doors locked - nearly had heart failure!


Our Xantia came with only one key, a disaster if it got lost. The only place able to cut a spare Xantia key was a 'Mr Minnit' branch (£8 IIRC) - very obliging too. I must admit I didn't try a Citroen dealer because I expected a new key/remote to be prohibitively expensive even if available.


The huge IR component of sunlight (even on a cloudy day) tends to 'swamp' the remote's signal making it harder for the sensor to detect. I've found that if the sun is shining and and there are rain drops on the glass to scatter both sunlight and signal, I have to put the remote right up to a window to get it to work. Clean, dry glass and no sun, the plipper works at 10 yards plus - even further at night!

Reduced range may mean that the two 3V Lithium 'button' cells (CR2025) need replacing. CR2032 batteries can be squeezed in as an alternative if desired.